Analysis And Synthesis Of Networked Control Systems With Event-Triggering Scheme

In order to reduce the unnecessary waste of the limited network bandwidth resources, in recent years, more and more researchers have focused their attention on the event-triggered control in the context of networked control systems (NCSs), and a number of important pieces of work have been reported. These pieces of work have significant importance on both the-oretical development and practical applications of event-triggering schemes in NCSs. Nev-ertheless, it is worth noting that the results obtained for event-triggered NCSs are still very limited:(ⅰ) most of the event-triggering conditions proposed in existing work have to be monitored continuously and the implementation of such event-triggering schemes requires dedicated analogue hardware to detect events, while few works propose an event-triggering condition that is checked only at an equidistant time instant, which leads to some advan-tages, such as a guaranteed minimum inter-event time of (at least) the sampling interval of the event-triggering condition, and it can be implemented in more standard time-sliced embedded software architectures; (ⅱ) most of the obtained results focus on stability analysis of event-triggered NCSs, while few papers solve the problems of controller synthesis and filter design, which are more useful and challenging than the stability issue; (ⅲ) most of the existing results are only applicable for deterministic systems, while few papers consider the event-triggering in NCSs with parameter uncertainties, which is more general and realistic than previous work.Motivated by the above observations, to shorten such a gap, it is necessary to investigate how to improve the existing event-triggering conditions and solve the controller synthesis and filter design problems. In this dissertation, from the synthesis point of view, we introduce some novel event-triggering schemes to improve the resource utilization, and develop some approaches to considering the event-triggering scheme and controller synthesis and filter de-sign of networked systems in a unified framework. The main contents of this dissertation are outlined as follows:The L2-gain analysis problem for a class of linear NCSs with event-triggering scheme in the presence of time-varying transmission delays is investigated, where the results on expo- nential stability analysis and L2-gain analysis are derived in terms of LMIs. Furthermore, we discuss how to extend the obtained results to the system with parameter uncertainties, and also discuss how to design the feedback gain matrix. Finally, on the basis of the previous results on single event-triggering scheme (only introduced in the sensor side), we further investigate two different event-triggering schemes are introduced in the sensor side and controller side, respectively. A novel event-triggered NCSs model is established with simultaneous consid-eration of two event-triggering schemes and the time-varying transmission delays. Based on this model, we further study the L2-gain analysis problem.The event-triggered control problem for a class of uncertain linear NCSs with quantiza-tions in the presence of time-varying transmission delays is studied, and the sufficient con-ditions are derived for the existence of the desired controller. Based on these conditions, the co-design method for the feedback gain of the controller and triggering parameter is proposed.The event-based H∞filtering problem is addressed for a class of wireless sensor net-works with time-varying transmission delay. A new event-triggering mechanism is proposed and a novel filtering error system model is established to account for both the event-triggering condition and time-varying transmission delay in a unified framework. Then, based on this model, by using Lyapunov functional approach together with LMI technique, both of the sta-bility and H∞performance are analyzed for the event-triggered filtering error system. The desired H∞filter is designed.The problem of robust guaranteed cost control for a class of uncertain linear discrete-time NCSs with event-triggering scheme is studied. An event-triggering scheme is first proposed. Then considering the effects of transmission delays and event-triggering scheme, by using delay system approach, we convert the closed-loop event-triggered control system into a dis-crete time-delay system. Finally, both the stability and controller synthesis of such time-delay system are analyzed by the well-developed theory on time-delay systems.Finally, we summarize the results of the dissertation and propose some problems that are worth further study.